A common theme of questions I’m seeing about iOS 5 relates to how well the update plays with shared family devices and Apple ID accounts. While it can be a bit confusing to negotiate, the questions only serve to underline that people often use Apple’s mobile products in shared family situations. And iOS 5 and iCloud seek to acknowledge and capitalize on that aspect of their appeal.

iMessage keeps everyone in the loop

With Apple’s new group messaging/SMS and MMS replacement iMessage, family members can stay in close contact quickly and easily. The beauty of the system is that even if children are too young to necessarily have a smartphone, they can still join in the family conversation, since iPads and iPod touches connected to Wi-Fi can communicate through iMessage, independent of any cellular network.

For families where some members spend a lot of time travelling, or where different members live in different households, this is a great way to keep up communication between people who might not otherwise be able to talk as often. Plus, thanks to group messaging features, you can use iMessage as a virtual family message board, or target just the kids or just the adults separately from everyone else.

Find My Friends can reassure, help coordinate

I’m not entirely sure that knowing where your kids are all the time is necessarily a great idea, but Find My Friends can help make letting them go out on that first date a little easier. Also, when the family’s on vacation, Find My Friends can help everyone feel a little more secure when venturing out on their own for day trips or independent excursions.

Finally, Find My Friends could help family members coordinate, too. You could use it to see if you’re nearby to one another if you’re in an unfamiliar neighborhood and want to meet up for lunch, or if someone calls for a ride and aren’t sure how to get there or what the exact address is.

Reminders creates shared task lists

If you set up a shared iCloud account for your family, you can sync Reminders lists between devices, resulting in a shared to-do list. This could be for grocery shopping, errands to run on the way home, projects for the weekend, or whatever else you need to get done working in concert with other family members.

Since you can add notes to Reminders, you can even add greater specificity to tasks, and thanks to ge0-fencing, one partner could easily set a task to pick up milk that notifies the other to complete it when they leave work for the day. Sharing one iCloud account between family members may not work for everyone, but for a small family or a couple without much need for independent calendars or contacts, it could be perfect.

Past purchases and iTunes Match help share and share alike

It isn’t yet live for the general public, but when iTunes Match arrives, it’ll be possible to share one music library between multiple iOS devices in the cloud. If you share an iTunes store account, all members of the family will be able to download music from your iTunes library selectively to their own devices. That means you can have a general pool of all your music, and people can pick and choose what they like, by song, album, artist or playlist.

Even before iTunes Match arrives, past purchases in the iTunes, App and iBooks Stores will make it easier for family members to pool their resources and share media buying duties for their iOS devices. You can easily do this by sharing one iTunes Store account, and keeping iCloud, iMessage and FaceTime associated with separate credentials if you don’t want those things to work across all devices. Gone are the days when Junior buys Pages even though Father already has it.

The family that computes together buys together

Apple is very smart to make iOS, iCloud and its devices more appealing to families; it extends the concept of platform lock-in beyond the individual and applies it to a whole group. If iOS-only services make life easier for a family in terms of communication, the daily grind and keeping everyone entertained, then users will probably be even less likely to switch to other platforms down the road.